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package com.sun.mail.util;

import java.util.*;
import javax.mail.Session;

/**
 * Utilities to make it easier to get property values.
 * Properties can be strings or type-specific value objects.
 * 
 * @author Bill Shannon
 */
public class PropUtil {

	// No one should instantiate this class.
	private PropUtil() {
	}

	/**
	 * Get an integer valued property.
	 */
	public static int getIntProperty(Properties props, String name, int def) {
		return getInt(getProp(props, name), def);
	}

	/**
	 * Get a boolean valued property.
	 */
	public static boolean getBooleanProperty(Properties props, String name, boolean def) {
		return getBoolean(getProp(props, name), def);
	}

	/**
	 * Get an integer valued property.
	 */
	public static int getIntSessionProperty(Session session, String name, int def) {
		return getInt(getProp(session.getProperties(), name), def);
	}

	/**
	 * Get a integer valued System property.
	 */
	public static int getIntSystemProperty(String name, int def) {
		try {
			return getInt(getProp(System.getProperties(), name), def);
		} catch (Exception e) {
			return def;
		}
	}

	/**
	 * Get a boolean valued property.
	 */
	public static boolean getBooleanSessionProperty(Session session, String name, boolean def) {
		return getBoolean(getProp(session.getProperties(), name), def);
	}

	/**
	 * Get a boolean valued System property.
	 */
	public static boolean getBooleanSystemProperty(String name, boolean def) {
		try {
			return getBoolean(getProp(System.getProperties(), name), def);
		} catch (SecurityException sex) {
			// fall through...
		}

		/*
		 * If we can't get the entire System Properties object because
		 * of a SecurityException, just ask for the specific property.
		 */
		try {
			String value = System.getProperty(name);
			if (value == null)
				return def;
			if (def)
				return !value.equalsIgnoreCase("false");
			else
				return value.equalsIgnoreCase("true");
		} catch (SecurityException sex) {
			return def;
		}
	}

	/**
	 * Get the value of the specified property.
	 * If the "get" method returns null, use the getProperty method,
	 * which might cascade to a default Properties object.
	 */
	private static Object getProp(Properties props, String name) {
		Object val = props.get(name);
		if (val != null)
			return val;
		else
			return props.getProperty(name);
	}

	/**
	 * Interpret the value object as an integer,
	 * returning def if unable.
	 */
	private static int getInt(Object value, int def) {
		if (value == null)
			return def;
		if (value instanceof String) {
			try {
				return Integer.parseInt((String) value);
			} catch (NumberFormatException nfex) {
			}
		}
		if (value instanceof Integer)
			return ((Integer) value).intValue();
		return def;
	}

	/**
	 * Interpret the value object as a boolean,
	 * returning def if unable.
	 */
	private static boolean getBoolean(Object value, boolean def) {
		if (value == null)
			return def;
		if (value instanceof String) {
			/*
			 * If the default is true, only "false" turns it off.
			 * If the default is false, only "true" turns it on.
			 */
			if (def)
				return !((String) value).equalsIgnoreCase("false");
			else
				return ((String) value).equalsIgnoreCase("true");
		}
		if (value instanceof Boolean)
			return ((Boolean) value).booleanValue();
		return def;
	}
}
